Inductance system



y 7, 1932. L. A. GEBHARD ET AL 1,353,492

INDUCTANCE SYSTEM Fil ed April 18, 1950 2 Sheets-Sheet 1 I Jwwawvfo m k o a $256M) sf a 5144001604? Q3 \f 8 BY m w w 1 Q ATTORNEY y 1932. L. A. GEBHARD ET AL 1,858,492

INDUCTANCE SYSTEM Filed April 18, 1930 2 Sheets-Sheet 2 BY l Q5 ATTORNEY Patented May 17, 1932 UNITED STATES PATENT .FFIQE LOUIS A. GEBHAR-D AND CORR-IE F. RUDOLPH, OF WASHINGTON, DISTRICT OF CO- LUIZEBIA, ASSIGNOBS'TQ WIRED HADES, INC, OF NEW 203K,

OF DELAWARE N. Y., .A. CORPORATION INDUCTANOE SYSTEM Application filed April 18,

Our invention relates broadly high frequency inductance systems and more particularly to a construction of continuously variable high frequency inductance coil for short wave radio transmitters.

One of the objects of our invention is to provide a construction of high frequency inductance system which is efhcient in its operation and is provided with a high degree of insulation.

Another object of our invention is to provide a construction of high frequency inductance in which an extremely accurate value of inductance may be effectively selected for connection into a transmitter circuit with means fo insulatingly supporting the inductance for preventing losses of energy and conser ing power in the transmitting system.

A further object of our invention is to provide a construction of mounting for a high frequency inductance system in which a frame of synthetic porcelain is assembled to support an inductance coil within a minimum overall physical dimension and in a manner by which a high degree of insulation for the parts of the inductance is assured.

A still further object of our invention is to provide an assembly for a high frequency inductance system wherein a minimum number of parts of synthetic porcelain are compactly arranged with respect to each other for insulatingly supporting an inductance coil, the synthetic porcelain parts being mechanically connected together in a rigid manner with parts abutting against accurately ground surfaces insuring the accurate assembly of the parts for accurately spacing the turns of the inductance and maintaining the turns thereof in selected spacial relation throughout the period of operation of the transmitter.

Other and further objects of our invention reside in the construction of high frequency inductance system as set forth more fully in the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 is a central vertical longitudinal- 1930. Serial No. 445,415.

ly sectional view through the inductance system with parts shown in side elevation and certain parts omitted for the purpose of ciearly illustrating the assembly of the inductance system; Fig. 2 is a detailed horizontal sectional view through the control mechanism for the inductance on line 22 of Fig. 1; Fig. 3 is an end elevation of the inductance support looking in the direction of arrow A in Fig. l; and Fig. 4 is a transverse vertical sectional view on line H of Fig. 1.

Experience has shown that inductance coils insulated with balrelite, wood, or similar insulation, are not satisfactory when subjected to climatic conditions of excessive lnoistur and excessive heat. We have found that insulating material such as synthetic porcelains when properly assembled to form an inductance frame will stand up under the most severe conditions, but in order to use this material the parts must be specially constructed.

The inductance of our invention is formed by a flat spiral ribbon indicated by reference character 1 wound edgewise as illus trated and supported by radially positioned spacer bars 2, 3, 4, 5, 6 and 7 as indicated more fully in Figs. 3 and 4. The spacer bars 2'? are mounted between end plates 9 and 10 by means of screw members 8 which pass through securing plates Sc bearing upon the outside face of t is end plates 9 and 10 forming the supporting plates for the inductance frame. The end plates 9 and 10 are each provided with radial slots 2a, 3a, 4a, a, 6a and 7a, one extremity of which terminates in the plane of the outside surfaces of the end plates 9 and and the other extremity of which terminates in oii'set faces 26, 3b, 4b, 5b, 6b, and 7?) against which the ends of spacer bars abut. Both end plates 9 and 10 have correspondingly arranged offset faces -72) which are ground on the synthetic porcelain plates to permit of an accurate alignment of the spacer bars therebetween. The induc tance l is wound edgewise in slots accurately spaced in the inner faces of the synthetic porcelain bars 2, 8, i, 5, 6 and 7 so that the inductance is supported in the manner more clearly illustrated in Fig. 4 interiorly of the frame formed by the multiplicity of longitudinally extending bars. The end plates 9 and 10 are supported from the frameworh of the transmi ter by means of angle members 11 and 12 and by means of bolt members 48 and 4-9 which pass theretl'irough. The end plate 9 is pr vided with a centr l be ing surface ground thereon as represented at 50 against which the bea ng plate 13 is mounted by means of screw iembers 14.. Th threaded shaft 15 is supported in the bearing plate 13 at one end by means of screw 16 and a pin 16a secured therethrough. The screw threaded shaft 15 passes concentric-ab 15 ly through a metallic tube 1'? which rotates over the threaded shaft 15 and over the nular projected portion 18 of the bearnig plate 13 which has been illustrated in F The other end of the tube 17 turns in a 29 ing 19 mounted in the end plate 20 which is secured by means of screws 21 and to the ground face 51 of the synthetic porcelain our plate 10. The bearing plate 20 is aperturei and screw thread-ed to receive the securing; screw 22 and has securing screw 21 passing therethrough and bolted thcreover as sh e-l. A plug 23 is fitted into the end or" the rou ing tube 17 and surrounding the tube 17 the is a ring 2-1 secured thereto by pin plug has a slot 26 in the end thereof on gaging with the universal joint shown The universal joint 27 is in the form of insulator having countersunk end porti us which receive the slotted end 26 of plug o at one end and the slotted end 28 of cranl-z. shaft 29 at the other end. The shaft which leads from the cran: 29 provided with a bevel gear 30 thereon which meshes with t bevel gear 31 of the counter which. can: ter records the number of turns through which the crank 29 is revolved, thereby eil abling the inductance selector contact to reset to any desired position as v 'll be more fully hereinafter explained. The cc mechanism is visible through a slot in panel l5 of the transmitter, en readings of the counter to be obse1 times. The counter and its gear m are carried by an auxiliary frame co by plate 55 which is in turn supper the end plate 10 by means of pedestal in 1 tor members 56. The pedestal insu are secured to the synthetic pore-era; plate 10 by means of screws Inasmu is the synthetic porcelain end plate mater; must be accurately ground to proper dimensions, every effort is made to accurately match the several parts in assembling the frame of the high frequency inductance syst'un. holes through which screws 5'7 pass are made larger than necessary in order to ail or ql adjustment of the alignment between counter and control. mechanisr The ing 17 has a longitudinally extending v is 17a cut therein through which the screw passes. The screw 33 is carried by a slider 34 and projects through the slot 17a in the tube 17 into the threads in shaft 15. The slider 34 carries bearing plate 35 by which the brush 36 is maintained in variable contacting alignment with the turns of the inductance 1. The brush 36 cons sts of metal springs 37 which engage opposite sides of the turns of the inductance 1 being secured in spaced relation by means of the metal arm 38. The metal arm 38 is pivotally connected at 39 with the plate 34. The plate 35 obstantially in the form of a solid angle haring arm 38 which carries the brush 36. Good electrical connection with each turn of inductance is assured by the gripping both sides of the turn of inductance by brush members 36. Pins are set in opposite ends of the thread in shaft 15 to serve as a stop to prevent the brush 36 from traveling to the en: of the coil. The ends of the induct-amp c 1 are fastened to spacer bars 2 by means 1 screws ll and 42 and metal project-Eng mourbers 43 and al.

In assembling the synthetic porcelain frame, the screws 8 are passed through washer members which are composite lead and brass preventing the chipping or breaking of the edge of the synthetic porcelain material around the sides of the slots while insuring the proper alignment of the parts. The oilset portions 26, 3b, 4b, 5b, 6b and 7?) on the inner face of end plate 9 and corresponding number of parts on the inner face of end plate 10, and offset portions and 51 on the inner faces of the end plates are ground to secure accurate alignment of the parts and proper assembly of the frame.

The synthetic porcelain which we use may be given a primary firing which makes it possible to readily machine the porcelain. After machining the synthetic porcelain is fired a second time during which process it becomes very hard so that it is diflicult to machine.

The synthetic porcelain, however, can be ground and it is for this reason that we provide the faces on the parts to permit grinding to proper dimensions in accurately assembling the parts of the frame. In the process of the second firing, a severe shrinkage occurs which may result in inaccuracies and warping but by grinding the parts after the second firing such inaccuracies and effects of warping may be eliminated. i

In some instances it is desirable to insert lead washers between the ends of spacer bars 2, 3, 4, 5, 6 and 7 and the end plates 9 and 10 to prevent excessive strains being set up in the material. The synthetic porcelain which we have selected for mounting the inductance system of our invention has a quality of high radio frequency resistance at extremely high frequencies. By reason of the shrinkage in firing, however, this material has heretofore been objectionable for the mounting of in- 139 ICC ductances but with the provision for grinding the several parts as set forth above, these defects have been eliminated by the arrangement of our invention.

It will be seen that adjustment of crank 29 from the front of the transmitter panel enables the brush 36 to be moved to any selected angular position along the inductance.

vVhile we have described our invention in certain preferred embodiments, we desire that itbe understood that modifications may be made and that nolimitations upon our invention are intended other than are imposed by the scope of the appended claims.

What we claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A high frequency inductance system comprising a frame structure including end plates of synthetic porcelain material, radially extending zones of porcelain formed on the adjacent faces of said end plates, longitudinally extending bars interconnecting said end plates, and disposed between correspondingly aligned radial zones of porcelain on the adjacent faces of said end plates, a helical inductance mounted upon said longitudinally extending bars, said bars each being formed from synthetic porcelain, and means for securing the ends of said bars with respect to the adjacent faces of each of said end plates.

In an inductance system, a frame structure comprising a pair of end plates of synthetic porcelain, angularly disposed zones of porcelain formed integral with adjacent faces of said end plates, bar members of synthetic porcelain interconnecting said end plates and disposed between the angularly disposed zones of porcelain formed thereon,

a helical inductance centrally positioned between said bar members, and means for securing the synthetic porcelain bar members at opposite ends thereof to the angularly disposed zones of porcelain on said synthetic porcelain end plates.

3. In a high frequency inductance system, a frame comprising a pair of synthetic porcelain end plates, offset faces on said end plates, bar members of synthetic porcelain extending between the offset faces on said end plates, means for securing said bar members to the offset portions of said end plates, and an inductance centrally positioned between said bar members.

4. In a high frequency inductance system, a pair of synthetic porcelain end plates having radially positioned slots formed therein, offset faces adjacent each of said slots, bar members of synthetic porcelain extending between the offset faces adjacent said slots, means for securing said bar members of synthetic porcelain material between said ofi'set faces, a helical inductance disposed between said bar members, and means journaled with respect to said end plates for selecting the effective number of turns in said inductance.

5. In a high frequency inductance system, a frame comprising a pair of end plates of synthetic porcelain, a multiplicity of offset faces on said end plates, slots disposed in said offset faces, bar members of synthetic porcelain secured in the slots between said offset faces, a helical inductance secured between said bar members centrally within said frame, and means j ournaled in said end members for selecting the effective number of turns in said inductance.

6. In a high frequency inductance system, a frame structure comprising a pair of synthetic porcelain end plates, bearing faces formed integral with said end plates and adapted to be ground to selected dimensions, spacer bars of synthetic porcelain extending between the bearing faces of said end plates, means for securing said spacer bars between said end plates, a helical inductance concentrically positioned between said bars and means supported by said end plates for selecting the effective number of turns in said inductance.

7. A high frequency inductance system comprising a pair of end plates of synthetic porcelain, bearing faces on said end plates directed toward each other and adapted to be ground to selected thicknesses, a multiplicity of spacer bars of synthetic porcelain extending between the bearing faces on said end plates, means securing said spacer bars in position, bearing plates supported by the bearing faces of said end plates, and means supported in said bearing plates for selecting the effective number of turns in said inductance.

8. In a high frequency inductance system, a frame structure comprising a pair of end plates each having bearing faces integrally formed thereon and adapted to be ground to selected dimensions, a multiplicity of spacer bars disposed between the bearing faces on said end plates, means securing said spacer bars in position with respect to the bearing faces on said end plates, a helical inductance disposed concentrically between said spacer bars and means supported from the bearing faces on said end plates for selecting the effective number of turns of said inductance.

9. In a high frequency inductance system a frame structure of synthetic porcelain comprising a pair of end plates each having offset faces directed toward each other, bearing plates carried by the offset faces of said end plates in axial alignment one with the other, a shaft member extending between said hearing plates, a multiplicity of spacer bars extending between bearing faces adjacent the periphery of said end plates, means for securing said spacer bars in position, an inductance centrally located between said spacer bars and means carried by said shaft for selecting the effective number of turns in said inductance.

10. In a high frequency inductance system, a frame structure of synthetic porcelain comprising a pair of end plates each having supporting faces directed. toward each other and offset from the plane of the end plates, a shaftmember eXtending centrally between said end plates, a multiplicity of spacer bars extending between supporting faces of said end plates adjacent the peripheries thereof, an inductance disposed centrally between said spacer bars and means guided by said shaft member for selecting the effective number of turns in said inductance.

11. In a high frequency inductance system,

a frame structure of synthetic porcelain comprising a pair of end plates each radially slotted adjacent the peripheries thereof, an

offset bearing face adjacent each slotted portion of said end plate, an offset bearing. face adjacent the center of each face, said offset 2 bearing faces each being adapted to be ground to required dimensions after firing of the synthetic porcelain material, spacer bars interconnecting the bearing faces of said end plates adjacent the peripheries thereof and secured tlierebetween, an inductance disposed between said spacer bars and a shaft member extending between the bearing plates carried by the centrally aligned bearing faces and having means thereon for selecting the effective number of turns of said inductance.

12. A high frequency inductance system i comprising a frame structure of synthetic porcelain possessing a high degree of shrinkage during firing, said frame structure ineluding a pair of end plates each having offset faces directed toward each other, mem bers extending between said faces and con stituting said frame structure, the members adjacent the peripheries of said plates constituting synthetic porcelain spacer bars, an inductance centrally supported by said bars and the member extending centrally be tween said. bearing faces including a movable contact device for selecting the effective number of turns in said inductance, each of said bearing faces being adapted to be ground to a selected dimension after the firing of the synthetic porcelain parts of said frame for accurately aligning and securing the sev eral parts of said frame together as a unit.

LOUIS A. GEBHARD. CORRIE F. RUDOLPH. 

